1. Field of the Invention
The present invention relates to a power management method and particularly to a power saving method for dynamically adjusting the time that an input device (a wireless mouse, for example) enters a power saving mode according to the usage states thereof.
2. Description of Related Art
In recent years, computer-related accessories are being developed to have wireless function. Wireless mice are especially popular among all. A wireless mouse features that the data in the mouse is transmitted back to the computer via wireless transmission, and therefore does not require a connection wire. However, without the connection wire, the wireless mouse can not receive power supply from the computer and has to rely on a battery as the power source, which is fairly limited. To prevent the inconvenience of replacing batteries or charging batteries frequently, it is necessary to take power consumption and power management into consideration when designing a wireless mouse, so as to extend the usage time of the mouse.
A commonly-adopted power saving method of wireless mice is to turn off a movement sensing module and a wireless transmission module for saving power when the mouse is idle, and activate the turned-off modules when a user clicks on the mouse. However, it is difficult to determine whether the mouse is idle. Generally, an idle timer is designed in the firmware of the mouse. The idle timer begins to count time when the mouse is not operated by the user, and allows the mouse to enter power saving mode when the mouse is idle over a predetermined time. The predetermined time of the timer is usually a fixed value. However, the user's patterns of operating the mouse may differ according to his/her purposes of use. If the predetermined time is set too short, the status of the mouse may not be judged accurately to comply with the user's operation which has a longer operating interval; on the contrary, if the predetermined time is set too long, the power saving efficiency may be impaired.